source: vendor/current/source4/ntvfs/sysdep/inotify.c

Last change on this file was 988, checked in by Silvan Scherrer, 9 years ago

Samba Server: update vendor to version 4.4.3
File size: 9.6 KB
Line 
1/*
2 Unix SMB/CIFS implementation.
3
4 Copyright (C) Andrew Tridgell 2006
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
18*/
19
20/*
21 notify implementation using inotify
22*/
23
24#include "includes.h"
25#include "system/filesys.h"
26#include <tevent.h>
27#include "ntvfs/sysdep/sys_notify.h"
28#include "../lib/util/dlinklist.h"
29#include "libcli/raw/smb.h"
30#include "param/param.h"
31
32#include <sys/inotify.h>
33
34/* glibc < 2.5 headers don't have these defines */
35#ifndef IN_ONLYDIR
36#define IN_ONLYDIR 0x01000000
37#endif
38#ifndef IN_MASK_ADD
39#define IN_MASK_ADD 0x20000000
40#endif
41
42struct inotify_private {
43 struct sys_notify_context *ctx;
44 int fd;
45 struct inotify_watch_context *watches;
46};
47
48struct inotify_watch_context {
49 struct inotify_watch_context *next, *prev;
50 struct inotify_private *in;
51 int wd;
52 sys_notify_callback_t callback;
53 void *private_data;
54 uint32_t mask; /* the inotify mask */
55 uint32_t filter; /* the windows completion filter */
56 const char *path;
57};
58
59
60/*
61 see if a particular event from inotify really does match a requested
62 notify event in SMB
63*/
64static bool filter_match(struct inotify_watch_context *w,
65 struct inotify_event *e)
66{
67 if ((e->mask & w->mask) == 0) {
68 /* this happens because inotify_add_watch() coalesces watches on the same
69 path, oring their masks together */
70 return false;
71 }
72
73 /* SMB separates the filters for files and directories */
74 if (e->mask & IN_ISDIR) {
75 if ((w->filter & FILE_NOTIFY_CHANGE_DIR_NAME) == 0) {
76 return false;
77 }
78 } else {
79 if ((e->mask & IN_ATTRIB) &&
80 (w->filter & (FILE_NOTIFY_CHANGE_ATTRIBUTES|
81 FILE_NOTIFY_CHANGE_LAST_WRITE|
82 FILE_NOTIFY_CHANGE_LAST_ACCESS|
83 FILE_NOTIFY_CHANGE_EA|
84 FILE_NOTIFY_CHANGE_SECURITY))) {
85 return true;
86 }
87 if ((e->mask & IN_MODIFY) &&
88 (w->filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)) {
89 return true;
90 }
91 if ((w->filter & FILE_NOTIFY_CHANGE_FILE_NAME) == 0) {
92 return false;
93 }
94 }
95
96 return true;
97}
98
99
100
101/*
102 dispatch one inotify event
103
104 the cookies are used to correctly handle renames
105*/
106static void inotify_dispatch(struct inotify_private *in,
107 struct inotify_event *e,
108 uint32_t prev_cookie,
109 struct inotify_event *e2)
110{
111 struct inotify_watch_context *w, *next;
112 struct notify_event ne;
113
114 /* ignore extraneous events, such as unmount and IN_IGNORED events */
115 if ((e->mask & (IN_ATTRIB|IN_MODIFY|IN_CREATE|IN_DELETE|
116 IN_MOVED_FROM|IN_MOVED_TO)) == 0) {
117 return;
118 }
119
120 /* map the inotify mask to a action. This gets complicated for
121 renames */
122 if (e->mask & IN_CREATE) {
123 ne.action = NOTIFY_ACTION_ADDED;
124 } else if (e->mask & IN_DELETE) {
125 ne.action = NOTIFY_ACTION_REMOVED;
126 } else if (e->mask & IN_MOVED_FROM) {
127 if (e2 != NULL && e2->cookie == e->cookie) {
128 ne.action = NOTIFY_ACTION_OLD_NAME;
129 } else {
130 ne.action = NOTIFY_ACTION_REMOVED;
131 }
132 } else if (e->mask & IN_MOVED_TO) {
133 if (e->cookie == prev_cookie) {
134 ne.action = NOTIFY_ACTION_NEW_NAME;
135 } else {
136 ne.action = NOTIFY_ACTION_ADDED;
137 }
138 } else {
139 ne.action = NOTIFY_ACTION_MODIFIED;
140 }
141 ne.path = e->name;
142
143 /* find any watches that have this watch descriptor */
144 for (w=in->watches;w;w=next) {
145 next = w->next;
146 if (w->wd == e->wd && filter_match(w, e)) {
147 ne.dir = w->path;
148 w->callback(in->ctx, w->private_data, &ne);
149 }
150 }
151
152 /* SMB expects a file rename to generate three events, two for
153 the rename and the other for a modify of the
154 destination. Strange! */
155 if (ne.action != NOTIFY_ACTION_NEW_NAME ||
156 (e->mask & IN_ISDIR) != 0) {
157 return;
158 }
159
160 ne.action = NOTIFY_ACTION_MODIFIED;
161 e->mask = IN_ATTRIB;
162
163 for (w=in->watches;w;w=next) {
164 next = w->next;
165 if (w->wd == e->wd && filter_match(w, e) &&
166 !(w->filter & FILE_NOTIFY_CHANGE_CREATION)) {
167 ne.dir = w->path;
168 w->callback(in->ctx, w->private_data, &ne);
169 }
170 }
171}
172
173/*
174 called when the kernel has some events for us
175*/
176static void inotify_handler(struct tevent_context *ev, struct tevent_fd *fde,
177 uint16_t flags, void *private_data)
178{
179 struct inotify_private *in = talloc_get_type(private_data,
180 struct inotify_private);
181 int bufsize = 0;
182 struct inotify_event *e0, *e;
183 uint32_t prev_cookie=0;
184
185 /*
186 we must use FIONREAD as we cannot predict the length of the
187 filenames, and thus can't know how much to allocate
188 otherwise
189 */
190 if (ioctl(in->fd, FIONREAD, &bufsize) != 0 ||
191 bufsize == 0) {
192 DEBUG(0,("No data on inotify fd?!\n"));
193 return;
194 }
195
196 e0 = e = talloc_size(in, bufsize);
197 if (e == NULL) return;
198
199 if (read(in->fd, e0, bufsize) != bufsize) {
200 DEBUG(0,("Failed to read all inotify data\n"));
201 talloc_free(e0);
202 return;
203 }
204
205 /* we can get more than one event in the buffer */
206 while (bufsize >= sizeof(*e)) {
207 struct inotify_event *e2 = NULL;
208 bufsize -= e->len + sizeof(*e);
209 if (bufsize >= sizeof(*e)) {
210 e2 = (struct inotify_event *)(e->len + sizeof(*e) + (char *)e);
211 }
212 inotify_dispatch(in, e, prev_cookie, e2);
213 prev_cookie = e->cookie;
214 e = e2;
215 }
216
217 talloc_free(e0);
218}
219
220/*
221 setup the inotify handle - called the first time a watch is added on
222 this context
223*/
224static NTSTATUS inotify_setup(struct sys_notify_context *ctx)
225{
226 struct inotify_private *in;
227 struct tevent_fd *fde;
228
229 in = talloc(ctx, struct inotify_private);
230 NT_STATUS_HAVE_NO_MEMORY(in);
231
232 in->fd = inotify_init();
233 if (in->fd == -1) {
234 DEBUG(0,("Failed to init inotify - %s\n", strerror(errno)));
235 talloc_free(in);
236 return map_nt_error_from_unix_common(errno);
237 }
238 in->ctx = ctx;
239 in->watches = NULL;
240
241 ctx->private_data = in;
242
243 /* add a event waiting for the inotify fd to be readable */
244 fde = tevent_add_fd(ctx->ev, in, in->fd,
245 TEVENT_FD_READ, inotify_handler, in);
246 if (!fde) {
247 if (errno == 0) {
248 errno = ENOMEM;
249 }
250 DEBUG(0,("Failed to tevent_add_fd() - %s\n", strerror(errno)));
251 talloc_free(in);
252 return map_nt_error_from_unix_common(errno);
253 }
254
255 tevent_fd_set_auto_close(fde);
256
257 return NT_STATUS_OK;
258}
259
260
261/*
262 map from a change notify mask to a inotify mask. Remove any bits
263 which we can handle
264*/
265static const struct {
266 uint32_t notify_mask;
267 uint32_t inotify_mask;
268} inotify_mapping[] = {
269 {FILE_NOTIFY_CHANGE_FILE_NAME, IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
270 {FILE_NOTIFY_CHANGE_DIR_NAME, IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
271 {FILE_NOTIFY_CHANGE_ATTRIBUTES, IN_ATTRIB|IN_MOVED_TO|IN_MOVED_FROM|IN_MODIFY},
272 {FILE_NOTIFY_CHANGE_LAST_WRITE, IN_ATTRIB},
273 {FILE_NOTIFY_CHANGE_LAST_ACCESS, IN_ATTRIB},
274 {FILE_NOTIFY_CHANGE_EA, IN_ATTRIB},
275 {FILE_NOTIFY_CHANGE_SECURITY, IN_ATTRIB}
276};
277
278static uint32_t inotify_map(struct notify_entry *e)
279{
280 int i;
281 uint32_t out=0;
282 for (i=0;i<ARRAY_SIZE(inotify_mapping);i++) {
283 if (inotify_mapping[i].notify_mask & e->filter) {
284 out |= inotify_mapping[i].inotify_mask;
285 e->filter &= ~inotify_mapping[i].notify_mask;
286 }
287 }
288 return out;
289}
290
291/*
292 destroy a watch
293*/
294static int watch_destructor(struct inotify_watch_context *w)
295{
296 struct inotify_private *in = w->in;
297 int wd = w->wd;
298 DLIST_REMOVE(w->in->watches, w);
299
300 /* only rm the watch if its the last one with this wd */
301 for (w=in->watches;w;w=w->next) {
302 if (w->wd == wd) break;
303 }
304 if (w == NULL) {
305 inotify_rm_watch(in->fd, wd);
306 }
307 return 0;
308}
309
310
311/*
312 add a watch. The watch is removed when the caller calls
313 talloc_free() on *handle
314*/
315static NTSTATUS inotify_watch(struct sys_notify_context *ctx,
316 struct notify_entry *e,
317 sys_notify_callback_t callback,
318 void *private_data,
319 void *handle_p)
320{
321 struct inotify_private *in;
322 int wd;
323 uint32_t mask;
324 struct inotify_watch_context *w;
325 uint32_t filter = e->filter;
326 void **handle = (void **)handle_p;
327
328 /* maybe setup the inotify fd */
329 if (ctx->private_data == NULL) {
330 NTSTATUS status;
331 status = inotify_setup(ctx);
332 NT_STATUS_NOT_OK_RETURN(status);
333 }
334
335 in = talloc_get_type(ctx->private_data, struct inotify_private);
336
337 mask = inotify_map(e);
338 if (mask == 0) {
339 /* this filter can't be handled by inotify */
340 return NT_STATUS_INVALID_PARAMETER;
341 }
342
343 /* using IN_MASK_ADD allows us to cope with inotify() returning the same
344 watch descriptor for muliple watches on the same path */
345 mask |= (IN_MASK_ADD | IN_ONLYDIR);
346
347 /* get a new watch descriptor for this path */
348 wd = inotify_add_watch(in->fd, e->path, mask);
349 if (wd == -1) {
350 e->filter = filter;
351 return map_nt_error_from_unix_common(errno);
352 }
353
354 w = talloc(in, struct inotify_watch_context);
355 if (w == NULL) {
356 inotify_rm_watch(in->fd, wd);
357 e->filter = filter;
358 return NT_STATUS_NO_MEMORY;
359 }
360
361 w->in = in;
362 w->wd = wd;
363 w->callback = callback;
364 w->private_data = private_data;
365 w->mask = mask;
366 w->filter = filter;
367 w->path = talloc_strdup(w, e->path);
368 if (w->path == NULL) {
369 inotify_rm_watch(in->fd, wd);
370 e->filter = filter;
371 return NT_STATUS_NO_MEMORY;
372 }
373
374 (*handle) = w;
375
376 DLIST_ADD(in->watches, w);
377
378 /* the caller frees the handle to stop watching */
379 talloc_set_destructor(w, watch_destructor);
380
381 return NT_STATUS_OK;
382}
383
384
385static struct sys_notify_backend inotify = {
386 .name = "inotify",
387 .notify_watch = inotify_watch
388};
389
390/*
391 initialialise the inotify module
392 */
393NTSTATUS sys_notify_inotify_init(void);
394NTSTATUS sys_notify_inotify_init(void)
395{
396 /* register ourselves as a system inotify module */
397 return sys_notify_register(&inotify);
398}
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